The present invention relates to printing apparatus and to printing apparatus for use with item/document sorter reader devices. More specifically, the present invention has to do with printing apparatus for indicating an error in data printed on items such as bank checks or similar documents which are magnetically or optically encoded and wherein the coded data is incorrectly disposed on the item for one reason or another. Still more specifically, the invention has to do with an inked ribbon transport mechanism for such printing apparatus and to a novel, demountable, disposable, endless ribbon transport error indicating device for use in item/sorter printing apparatus.